A detector cannot know which software was open while you typed. It reads the finished text and estimates how predictable the word choices are. Using autocomplete does not identify the text as machine output, but detectors can still misclassify human writing.
What a detector actually measures
These tools look at statistical properties of the text: how predictable each word is given the ones before it, how much the sentence lengths vary, how wide the vocabulary is. Text generated by a language model tends to sit in the high-probability middle of those distributions, because that is what the model is built to produce. Human writing wanders more.
That is a judgement about the text, not a record of how it was produced. Nothing in a document says which keystrokes came from a suggestion — and equally, nothing protects writing that happens to be plain and regular.
The research is not kind to detectors
An independent evaluation by Liang, Yuksekgonul, Mao, Wu and Zou at Stanford was published in Patterns in 2023. They ran seven widely used detectors over 91 TOEFL essays written by people and 88 essays by US eighth-graders, also written by people.
- The eighth-grade essays were classified accurately — about 5.1% were wrongly flagged.
- The TOEFL essays were not: the average false-positive rate was 61.3%.
- All seven detectors agreed in wrongly flagging 19.8% of the TOEFL essays.
- At least one detector flagged 97.8% of them.
The authors attribute this result to the features the detectors use. Limited vocabulary range and predictable sentence structure can appear machine-like to a detector, but they are also common in writing produced in a second language. The tools therefore risk penalising human writing for its statistical plainness.
That study is from 2023 and detectors have changed since. What has not changed is the shape of the problem: these are probabilistic classifiers, and none of them publishes a per-document error rate you could rely on to accuse someone.
So where does autocomplete sit
It depends entirely on how much of the text is yours.
| What you did | What the detector sees |
|---|---|
| Accepted a few word completions in sentences you composed | Your writing, with your structure and vocabulary |
| Accepted a phrase now and then to finish a routine sentence | Mostly your writing; routine sentences are routine either way |
| Asked a chatbot to write the paragraph and pasted it | Generated text, because it is generated text |
| Wrote it yourself, plainly, in a second language | Possibly flagged anyway — see above |
The relevant distinction is whether you composed the text yourself. Finishing your own sentence with a suggestion retains your composition, while asking for and accepting a generated paragraph does not.
If you are being assessed on originality
- Find out the actual rule. Many institutions permit spelling, grammar and predictive-text assistance and prohibit generated content. Some prohibit everything. A written rule is worth more than an assumption in either direction.
- Keep your version history. Google Docs and Word both keep one. A document that grew over hours, with additions, deletions and sentences written twice, is a record of the writing happening — which is a different kind of evidence from a score, and one a score cannot answer.
- Do not rewrite to beat a detector. Padding sentences with unusual words to lower a score makes your writing worse and is indistinguishable from what a “humanizer” tool does. If you are accused, the version history is the answer.
- Treat a score as a starting point for a conversation, not a verdict. Given false-positive rates like those above, that is all it can honestly be.
Where a local autocomplete differs
One practical difference has nothing to do with detection. Cloud writing assistants send what you type to a server to generate their suggestions. Typeahead runs a compact model on your own PC through llama.cpp, so once a model is downloaded, nothing you write is transmitted anywhere and it works with no connection at all.
It suggests the next few words of the sentence you are already writing, next to the caret, and inserts nothing unless you press Tab. It does not generate paragraphs, and it has no “write this for me” function — which is the feature that would actually put generated text in your document.
None of that guarantees a particular detector result. Your sentences remain on your machine, and the tool does not include a function that generates paragraphs for you.